Mr. T. Atthey on Anthracosaums Russelli. 165 



running inwards and backwards to the fissure which divides 

 into two parts tlie condyle for articulation with the mandible. 



About half a dozen isolated teeth of Anthracosaurus have been 

 found, which shows how very rare this amphibian is Avhen 

 compared with Loxomma, whose teeth are not unfrequently 

 met with. 



Vertehrce : six sej)arate ones, and on one small piece of shale 

 there is imbedded a quite entire vertebra ; there are also four 

 fragments of vertebral processes, some of which are articular. 



Ribs : four, in a good state of preservation, showing both 

 head and tubercle, and the remains of two others, one of which 

 shows head and tubercle. 



Scutes : in a small piece of shale are imbedded ten, well 

 preserved, but not lying in natural order ; and on separate 

 pieces of shale six or eight more. 



The scutes oi Anthracosaurus ^ Plate VIII. figs. 2 & 3, are 

 much like those which, since the publication of the description 

 of Loxomma, have occasionally been found in connexion with 

 the remains of the latter ; but they have not as yet been identi- 

 fied as belonging to Loxomma. 



Besides the above osseous remains of Anthracosaurus , and 

 lying scattered among the vertebrce, there is a good deal of 

 coprolitic matter, perhaps from the intestines ; and mixed up 

 with it are a palate-tooth, a rib, and several fragments of scales, 

 belonging to Ctenodus. 



Can it safely be inferred from these accompaniments that 

 Ctenodus ioxruQ^i at least a part of the food oi Anthracosaurus^ 



Note. — Of the three large Labyrinthodonts as yet found in 

 the Northumberland coal-field, Anthracosaurus is by far the 

 largest. The general arrangement of the separate bones which 

 form the upper surface of the cranium is much the same in 

 both Anthracosaurus and Loxomma ; but it differs considerably 

 from that of Fteroplax^ whose entire cranium, so far as we 

 know from specimens up to the present time obtained, is com- 

 posed of the bones corresponding to those which form the 

 centre or middle posterior part of the crania of the two former, 

 viz. the frontals, parietals, occipitals, postfrontals, squamous, 

 and epiotics. The posterior lateral expansions, composed of 

 postorbital, supratemporal, quadrate, and quadrate-jugal bones, 

 do not exist in this very interesting amphibian ; the pre- 

 maxillary, maxillary, nasal, and prefrontal bones also, which 

 form the anterior extremity of the cranium, have been broken 

 off, strange to say, from all the three specimens as yet known, 

 Pteroplax therefore differs considerably in. size,. in outline, and 

 in many details from both Anthracosaunis and Loxomma. 



Ann. d) Mag. N. Hist. Ser. 4. Vol. xviii. 12 



